Grasp Representations Depend on Knowledge and Attention

Seeing pictures of objects activates the motor cortex and can have an influence on subsequent grasping actions. However, the exact nature of the motor representations evoked by these pictures is unclear. For example, action plans engaged by pictures could be most affected by direct visual input and computed online based on object shape. Alternatively, action plans could be influenced by experience seeing and grasping these objects. We provide evidence for a dual-route theory of action representations evoked by pictures of objects, suggesting that these representations are influenced by both direct visual input and stored knowledge. We find that that familiarity with objects has a facilitative effect on grasping actions, with knowledge about the object's canonical orientation or its name speeding grasping actions for familiar objects compared to novel objects. Furthermore, the strength of contributions from each route to action can be modulated by the manner in which the objects are attended. Thus, evocation of grasping representations depends on an interaction between one's familiarity with perceived objects and how those objects are attended while making grasp actions.